The purpose of this proposal is to continue and to extend the strong core program in biometrical (biostatistical) phases of cancer epidemiology which is currently underway. The three main current objectives are: (1) Continued development of biostatistical technology that will facilitate each of the 9 basic steps in the overall process of data-utilization. The computer-assisted technology that has been evolved to date has greatly reduced the drudgery and increased the speed of access to the major data-bases that the Biostatistics Department has used to develop and test new techniques. While this has opened up some of the clerical bottlenecks, there are limiting factors appearing at other steps--particularly in the steps requiring conceptualization, abstraction, and communication in succinct but coherent form. The emphasis thus is shifting from tactical to strategic aspects of the overall process of data-utilization. (2) Continued development of biometric methods that are specially suited to the questions, data, and working hypotheses of a given area of study has led to "in depth" analysis of the role of environmental factors such as radiation. Each time a new "layer" is mined, there seems to be an even more important and useful layer just underneath. Mining it requires new concepts and procedures. (3) The acid test of technology, for truth-telling or any other purpose, is that it produces practical results. The technology here continues to yield new findings on radiation hazards, occupational hazards, carcinogens and co-carcinogens (cigarette smoking and alcoholic